JP3104655U - screw - Google Patents

Abstract

The object of the present invention is to form a screw thread in a square shape to improve the balance and accuracy of screwing, increase the contact area with wood in a screwed state, improve the pull-out resistance due to friction with wood, and manufacture by rolling. Provides easy screws.
A screw thread (5) provided on the outer peripheral surface of a circular shaft portion (4) is formed so that the shape of the outer periphery in a transverse cross section is quadrangular. A protruding portion 6 having a large amount of protrusion and a portion 7 having a small amount of protrusion with respect to both surfaces in the axial direction are provided alternately and repeatedly, and the protrusion 6 has a ridge line 8 in which both surfaces in the axial direction extend along the radial direction. The inclined surfaces 10 and 11 descend in the circumferential direction toward the portions where the amount of protrusion is small on both sides at the boundary, and the ridge line 8 of the raised portion 6 coincides with each square corner of the screw thread 5.
[Selection] Figure 2

Description

  The present invention relates to a screw which is used by being screwed into wood, and more particularly, to a screw which is formed in a square shape and which can perform tapping operation with a small force and high precision and at the same time has excellent pull-out resistance after screwing.

  Generally, a screw for wood has a structure in which a helical circular screw thread is provided on the outer peripheral surface of a circular shaft portion having a head at one end and a tip at the other end, and a tool engagement groove formed on the head. The screw is screwed into the wood from the tip by rotating the screw with the rotating tool to fix the workpiece.

  By the way, since the above-mentioned spiral circular screw thread enters at the time of tapping with respect to wood, the contact portion between the screw thread and the wood sequentially increases in accordance with the progress of screwing, and the screwing resistance is increased. In particular, it is difficult to screw into hard wood.

  In order to solve the problem of the screw having such a helical circular thread, a thread provided on the outer peripheral surface of the circular shaft portion is formed in a triangle, and the space between each pointed portion of the triangle and the circular shaft portion is formed. Raised screws have been proposed.

When such threads are formed in a triangular shape, the radius of each peak is maximized, and the radius of the threads is changed so that the radius between the peaks is minimized. By cutting the wood at the shape and the protruding portion, the contact portion between the screw thread and the wood can be reduced, and there is an advantage that the screw can be screwed more easily than the above-mentioned screw of the circular thread (see Patent Document 1). ).
Japanese Utility Model Registration No. 3078986

However, in the case of a screw in which the above-mentioned screw thread is formed in a triangular shape, wood is cut at three-pointed ridges and ridges, so that the load on each ridge and ridge at the time of screwing increases. Since the shape of the thread is almost non-circular, there is a problem that the balance and accuracy of screwing are poor.

  Further, the thread formed in a triangular shape has a problem in that the contact area with the wood in the screwed state is reduced, and therefore, the pull-out resistance due to friction with the wood does not increase.

  Furthermore, screws are generally manufactured by rolling, but triangular threads have a non-circular shape, so the rolling properties of the material during rolling are poor, and the formation of threads is technically difficult. It is difficult, especially, to machine the edge around the thread.

  Therefore, the problem of this invention is that the screw thread has a better balance and accuracy than a screw with a triangular thread, the contact area with the wood in the screwed state increases, the pull-out resistance due to friction with the wood improves, Moreover, it is an object of the present invention to provide a screw which can be easily manufactured by rolling and can reliably process an edge on the outer periphery of a screw thread.

  In order to solve the above problem, the invention of claim 1 is a screw in which a screw thread is spirally provided on an outer peripheral surface of a circular shaft portion having a head at one end and a tip at the other end, wherein the screw thread is The shape of the outer periphery in the cross section is formed in a quadrangular shape, and this screw thread protrudes at the quadrant in the circumferential direction, a protruding portion with a large amount of protrusion on both surfaces in the axial direction, and a protrusion on both surfaces in the axial direction. A portion having a small amount is alternately and repeatedly provided, and the raised portion is an inclined surface which is circumferentially lowered toward a portion with a small amount of protrusion on both sides of a ridge line along the radial direction on both sides in the axial direction. Is adopted in which the ridge line of each thread coincides with each square corner of the screw thread.

  Here, the head of the screw is provided with an engaging groove for a rotary tool, and the outer peripheral shape of the screw is square, so that the shape is close to a circle, so that the screwing balance and accuracy are good, and the screwing is good. In this state, the contact area with the wood increases, and the pull-out resistance due to friction with the wood improves.

  The invention of claim 2 employs a configuration in which the tangents between the inclined surfaces on both sides of the raised portion and the outer peripheral surface of the circular shaft portion are substantially linear in the circumferential direction.

  The invention according to claim 3 employs a configuration in which a tangential portion between the inclined surfaces on both sides of the raised portion and the outer peripheral surface of the circular shaft portion has an arcuate shape whose axial cross section is recessed.

  According to the invention of claim 4, the inclined surfaces on both sides of the raised portion are different in circumferential inclination angle between the inclined surface located at the front and the inclined surface located at the rear in the screwing rotation direction across the ridge line. The configuration adopts a configuration in which the inclined surface located is gentle and the inclined surface located at the rear is tight.

  In the invention according to claim 5, the cross-sectional shape along the axial direction of the raised portion of the screw thread and the portion with a small amount of protrusion is thinner from the outer surface of the circular shaft portion toward the outer peripheral edge, and the outer peripheral edge is edge-shaped. Is adopted.

  As described above, by forming the thread into a square shape, the shape becomes close to a circle, so that the screw can be easily manufactured by rolling and the edge can be reliably processed on the outer periphery of the thread.

  According to this invention, since the screw thread is formed in a square shape, the shape of the screw thread approaches a circle, and by approaching this circular shape, the balance and accuracy at the time of screwing of the screw thread are improved. As a whole mountain, the contact area with the wood increases due to the restoring force of the wood, and the pull-out resistance due to friction with the wood improves.

  Further, the screw thread is formed in a quadrangular shape, and at the circumferential quadrants of the screw thread, a protruding portion having a large overhang amount on both sides in the axial direction and a small protrusion amount on both sides in the axial direction. Since the parts are alternately and repeatedly provided, the screw thread cuts the fiber of the wood at the outer edge and the ridgeline of the raised part when screwing into the wood, and the raised part has both sides in the axial direction. Since the slopes that go down in the circumferential direction toward the parts with a small amount of overhang on both sides with the ridge line along the radial direction as the boundary, the slopes can reduce the amount of screw thread contact with the wood when screwing in, Thereby, the frictional resistance of the screw thread at the time of screwing is reduced, and it becomes easy to screw into wood.

  Furthermore, since the tangent line between the inclined surfaces on both sides of the raised portion and the outer peripheral surface of the circular shaft portion is substantially linear in the circumferential direction, the screw thread is substantially linear on the circular shaft portion side when the screw is screwed. The root portion pushes out the wood, and the entry of the screw thread can be made smoother.

  Furthermore, since the thread is formed in a square shape, the shape of the thread approaches a circle, the rolling property of the material at the time of rolling is good, manufacturing by rolling is easy, and the edge is securely processed on the outer periphery of the thread. can do

  The thread provided on the outer peripheral surface of the circular shaft portion has a quadrangular outer peripheral shape in the cross section, and the thread has a large amount of overhang on both sides in the axial direction at quadrants in the circumferential direction. Protrusions and portions having a small amount of protrusion with respect to both surfaces in the axial direction are alternately and repeatedly provided, and the protrusions are directed toward portions with small amounts of protrusion on both sides with a ridge line along both sides in the radial direction as a boundary. The ridge line of the raised portion coincides with each of the square corners of the thread.

  As shown in FIG. 1, the screw 1 of the present invention is provided with a screw thread 5 on the outer peripheral surface of a circular shaft portion 4 having a head 2 at one end and a tip 3 at the other end, and the screw thread 5 is circular. The shape of the outer periphery in the cross section of the shaft portion 4 is formed in a rectangular shape in plan view, and although not shown, the head 2 has a structure in which an engaging groove for a rotary tool is provided.

  As shown in FIGS. 1B and 2, the thread 5 has a large amount of overhang on both sides in the axial direction at the quadrants in the circumferential direction of the circular shaft portion 4, and has a large thickness. Protrusions 6 and portions 7 having a small amount of overhang with respect to both surfaces in the axial direction and having a reduced thickness are alternately provided repeatedly, and the protrusions 6 are separated by a ridge line 8 along which both surfaces in the axial direction extend along the radial direction. The inclined surfaces 10 and 11 descend in the circumferential direction toward the portions 7 with small overhangs on both sides, and the ridge lines 8 of the raised portions 6 coincide with the square corners of the screw thread 5.

  Further, the tangents between the inclined surfaces 10 and 11 on both sides of the raised portion 6 and the outer peripheral surface of the circular shaft portion 4 are substantially linear in the circumferential direction as shown in FIG. 2 (A) and 2 (B), a tangential portion between the inclined surfaces on both sides and the outer peripheral surface of the circular shaft portion 4 is an arc-shaped portion 9 whose axial cross section is recessed.

  The inclined surfaces on both sides of the raised portion 6 are different from each other in the circumferential direction of the inclined surface 10 located on the front and the inclined surface 11 located on the rear in the screwing rotation direction with the ridgeline 8 interposed therebetween. The surface 10 is loose, the inclined surface 11 located at the rear is tight, and the raised portion 6 of the thread 5 and the portion 7 with a small amount of overhang and the cross-sectional shape along the axial direction in the middle are all circular. The outer periphery of the shaft portion 4 becomes thinner from the outer surface to the outer periphery, and the outer periphery of the thread 5 has an edge 12.

  The screw of the present invention has the above-described configuration. The rotary shaft is engaged with the tool engagement groove formed in the head 2, and the circular shaft portion 4 is screwed from the tip by rotating the screw 1. It is screwed into wood to fix the object to be fastened.

  When the screw 1 is screwed in, the thread 5 screwed into the wood has a square outer shape when viewed in plan, so that the shape of the screw thread 5 approaches a circle, and In the screwed state, the contact area with the wood is increased by the restoring force of the wood in the screwed state, and the pull-out resistance due to the friction with the wood is improved.

  Further, the screw thread 5 is formed in a quadrangular shape, and a ridge 6 having a large amount of protrusion on both sides in the axial direction and a protrusion 6 on both sides in the axial direction at quadrants in the circumferential direction of the screw thread 5. By alternately and repeatedly providing the portions 7 having a small amount, the screw thread 5 cuts the fiber of the wood at the edge 12 of the outer periphery and the ridge line 8 of the raised portion 6 at the time of screwing into the wood, and moreover, The raised portion 6 has inclined surfaces 10 and 11 which are circumferentially lowered on both sides in the axial direction toward ridges 8 along the radial direction toward portions 7 on both sides with a small amount of overhang. Can reduce the amount of contact of the screw thread 5 with the wood at the time of screwing, thereby reducing the frictional resistance of the screw thread 5 at the time of screwing and making it easier to screw into the wood.

  Further, since the tangent line between the inclined surfaces 10 and 11 on both sides of the raised portion 6 and the outer peripheral surface of the circular shaft portion 4 is substantially linear in the circumferential direction, the screw shaft 5 has a circular shaft portion when the thread 5 is screwed. The substantially straight base portion on the fourth side pushes and spreads the wood, and the entry of the screw thread 5 can be made smoother.

  Furthermore, in the manufacture of the screw 1, since the screw thread 5 is formed in a quadrangular shape, the shape of the screw thread 5 approaches a circle, the rolling property of the material at the time of rolling is good, and the manufacturing by rolling is easy, and the screw thread 5 is easy to manufacture. 5, the edge 12 can be reliably machined on the outer periphery.

(A) is a front view of the screw, (B) is an enlarged cross-sectional plan view of the arrow II-II of (A). 1A is a longitudinal sectional front view of a screw thread enlarged along an arrow aa in FIG. 1B, and FIG. 1B is a longitudinal sectional front view of a screw thread enlarged along an arrow bb in FIG. 1B. Figure, (C) is an enlarged front view showing the shape of the thread provided on the screw.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Screw 2 Head 3 Tip 4 Circular shaft part 5 Screw ridge 6 Protruding part 7 Part which became thin with little overhang 8 Edge line 9 Arc-shaped part 10 Slope 11 Slope 12 Edge

Claims (5)

  In a screw in which a screw thread is helically provided on the outer peripheral surface of a circular shaft portion having a head at one end and a tip at the other end, the screw thread is formed so that the outer peripheral shape in a cross section is square, and the screw thread is At the quadrants in the circumferential direction, ridges with a large amount of overhang on both sides in the axial direction and portions with a small amount of overhang on both sides in the axial direction are provided alternately and repeatedly, and the ridge is Both sides in the direction are slopes that descend in the circumferential direction toward the part with less overhang on both sides with the ridge line along the radial direction as the boundary, and that the ridge line of this raised part matches each square corner of the thread Features screw.   2. The screw according to claim 1, wherein tangents between the inclined surfaces on both sides of the raised portion and the outer peripheral surface of the circular shaft portion are substantially linear in the circumferential direction.   The screw according to claim 1, wherein a tangential portion between the inclined surfaces on both sides of the raised portion and an outer peripheral surface of the circular shaft portion has an arcuate shape whose axial cross section is recessed.   The inclined surfaces on both sides of the raised portion have different circumferential inclination angles between the inclined surface located at the front and the inclined surface located at the rear in the screwing rotation direction across the ridge line, and the inclined surface located at the front is loose, The screw according to any one of claims 1 to 3, wherein an inclined surface located at a rear portion is tight.   The cross-sectional shape along the axial direction of the raised portion of the screw thread and the portion with a small amount of overhang is thinner from the outer surface of the circular shaft portion toward the outer peripheral edge, and the outer peripheral edge has an edge shape. The screw according to any one of claims 1 to 4, wherein:

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